1.13.3.1 Diagnostic Overview

An active hall sensor and a crank wheel, "e.g. 60 minus 2 teeth" detect the CKP. A reference gap, "e.g. of two teeth" allows the top dead center of Cylinder 0 to be detected. The CKP sensor delivers a certain number of high and low phases every 360°CKP. The transition from high to low is a falling edge, and from low to high is a rising edge. Only the falling edges are counted. The difference between two falling edges is 6° CKP.

The following malfunctions are detected: 

• missing CRK sensor signal P0335
• no plausible CRK signal P0336
• wrong tooth number P0370
• wrong tooth period P0370
• sync error P138F

A teeth counter is incremented at every falling edge of the CKP sensor signal. When plus or minus two teeth are detected during the previous 360° CKP at the reference gap, the tooth number de-bounce counter is incremented. When the counter exceeds the limit, a crankshaft tooth error is delivered to error management.

If more then two teeth plus or minus are detected, the crankshaft looses synchronization and a CKP synchronization de-bounce counter is incremented. When the counter exceeds the limit, a CKP synchronization error is delivered to error management.

An acceptance window detects a tooth period error. The expected tooth period is multiplied and divided with an engine speed dependency factor. The result is a bottom and a top limit of the tooth period, in which the transition from high to low of the electrical signal has to occur. When a tooth period is invalid, the tooth period error debounce counter is incremented. When the counter exceeds the limit, a crankshaft tooth per error is delivered to error management.

The detection of implausible CKP signals is based on the detection of CAM signals without receiving correct CKP signals. When 12 or more CAM edges are detected (e.g. 2 working cycles) without valid synchronization of the crankshaft, a CKP plausibility error is detected and delivered to error management. When no CKP signal at all is received, the symptom is either "missing signal" or "implausible signal".